In an electric car control apparatus for driving an induction motor, detection accuracy of a DC voltage is improved. A DC power supply device is provided which has a maximum potential terminal A, an intermediate potential terminal B, a minimum potential terminal C, an upstream side capacitor 6 between the maximum potential terminal A and the intermediate potential terminal B, and a downstream side capacitor 7 between the intermediate potential terminal B and the minimum potential terminal C. Also, an overvoltage suppression part is provided which includes a resistor 8 and a thyristor 9 between the maximum potential terminal A and the minimum potential terminal C. Further, provision is made for a downstream voltage sensor 10 between the intermediate potential terminal B and the minimum potential terminal C, an upstream voltage sensor 11 between a junction of the resistor 8 and the thyristor 9 and the intermediate potential terminal B, and a three level inverter 3 connected to the maximum potential terminal A, the intermediate potential terminal B and the minimum potential terminal C for supplying AC power to the induction motor. The three level inverter 3 is controlled by using detected voltages of the downstream voltage sensor 10 and the upstream voltage sensor 11.